Cruise control systems are designed to automatically control the speed of a vehicle. Specifically, with a cruise control system, the driver selects a desired interval to follow traffic as well as the desired cruise speed. When slower traffic is encountered, the cruise control system works to alter a vehicle speed to maintain the desired interval while following traffic. The vehicle speed is controlled by the cruise control system with moderate braking when needed.
When traffic clears, the cruise control system works to resume the desired cruise speed. The driver can override the system by braking at any time.
Such a cruise control system is normally designed to change its operation according to instructions sent from a plurality of driver operable switches.
For example, the plurality of driver operable switches are designed as push-button switches, and include a main switch, a cancel switch, a set switch, and a resume switch.
When pressed once under no cruise control being executed, the main switch sends, to the cruise control system, an instruction enabling the cruise control system to shift its operation mode to cruise-control ready mode in which the cruise control system waits for starting the cruise control.
When pressed once under cruise control being executed, the main switch sends, to the cruise control system, an instruction enabling the cruise control system to cancel or stop the cruise control.
When pressed, the cancel switch sends, to the cruise control system, an instruction enabling the cruise control system to cancel or stop the cruise control.
When pressed, the set switch sends, to the cruise control system, an instruction enabling the cruise control system to execute constant vehicle-speed control to thereby constantly set the vehicle speed at the current speed at the time of the set switch being pressed.
When pressed, the resume switch sends, to the cruise control system, an instruction enabling the cruise control system to resume the vehicle speed at a preset desired speed.
In addition, while the constant vehicle speed control is executed by the cruise control system by the pressing of the set switch, pressing the set switch one or more times sends, to the cruise control system, instructions enabling the cruise control system to, for example, accelerate the vehicle speed at one or more steps corresponding to the one or more times.
While the constant vehicle speed control is executed by the cruise control system by the pressing of the set switch, pressing the resume switch one or more times sends, to the cruise control system, instructions enabling the cruise control system to, for example, decelerate the vehicle speed at one or more steps corresponding to the one or more times.
In the configuration of the cruise control system, when the driver unintentionally presses either the set switch or resume switch while the cancel switch is being pressed or the main switch for canceling is being pressed, the set switch or resume switch being pressed enables the cruise control system to continue the corresponding cruise control despite of the driver's intention of canceling cruise control. This may cause the driver to mistrust in the cruise control system.
Thus, in order to address the problem set forth above, U.S. Pat. No. 5,170,859 corresponding to Japanese Patent Publication No. 2926064 discloses a constant-speed cruising system.
When at least two switches in the main switch, cancel switch, set switch and resume switch, are substantially simultaneously pressed, the constant-speed cruising system disclosed in the U.S. patent Publication is configured to disable the pressing of the at least two switches.
For example, it is assumed that, while the constant vehicle speed control is executed by the cruise control system by the pressing of the set switch, the driver tries to press the set switch for accelerating the vehicle speed, but simultaneously presses both the set switch and the resume switch in error.
In this assumption, the constant-speed cruising system disclosed in the U.S. patent Publication disables any of the set and resume switches being pressed.
In this assumption, focusing on the instant at which the set and resume switches are simultaneously pressed, when the resume switch is pressed, and thereafter the set switch is pressed, the constant-speed cruising system recognizes the pressing of the set switch as the latest driver's switch operation. That is, even though the constant-speed cruising system recognizes the latest driver's switch operation as intended by the driver, the constant-speed cruising control system disables the latest driver's switch operation, which may bring discomfort to the driver.